The present invention relates to multi-function rotary valves and, more particularly, relates to a random-access, dual, three-way, rotary switching valve for use with high-pressure liquid chromatography (HPLC), other analytical methods and the like.
A xe2x80x9cthree-wayxe2x80x9d switching valve provides a means for selectively routing a fluid input flow to the valve to one of two alternate output flows from the valve. A xe2x80x9crotaryxe2x80x9d valve is of the type wherein fluid flow is directed by rotating a valve rotor element to discrete angular positions relative to a stationary valve stator element. A xe2x80x9cdualxe2x80x9d rotary valve provides two valves in one valve body, both simultaneously operated by the positioning of the valve rotor. Rotary switching valves are commonly used, for example, in HPLC and other analytical methods to selectively direct a flow stream of one or more fluids along alternate paths to an analytical device or containment vessel.
One conventional type of dual, three-way, switching valve 220, as shown in FIG. 1, includes a disc-shaped rotor with a set of rotor grooves in the front face of the rotor that contacts, in a fluid-tight manner, the face of a cylindrically shaped stator body at a rotor-stator interface. Inlet passages and outlet passages, longitudinally bored through the stator body to the rotor-stator interface, are selectively fluidly coupled through the rotor grooves corresponding to the rotation of the rotor relative to the stator. Pivoting of the rotor enables the rotor grooves to fluidly couple selected passages of the stator, depending on their placement on the rotor and the angular position of the valve rotor. Model 7030 of Rheodyne, L. P. is an example of this type of switching valve.
In FIG. 1, valve 220 has a stator element 222 and a rotor 224. The stator element 222 defines a stator face 226 that opposes and is in fluid-tight contact with a rotor face 228 defined by rotor 224. The stator element 222 further defines a first inlet passage 230 that has one end 232 adapted to fluidly couple to a first fluid source (Not Shown) supplying a first fluid and has an opposite first inlet port 236 terminating at stator face 226. Similarly, stator element 222 further defines a second inlet passage 238 that has one end 240 adapted to fluidly couple to a second fluid source (Not Shown) supplying a second fluid and has an opposite second inlet port 244 terminating at stator face 226. The stator element 222 further defines a first outlet passage A, a second outlet passage B, a third outlet passage C, and a fourth outlet passage D, all in fluid communication with stator face 226.
The rotor 224, as shown, defines a first rotor groove 246 and a second rotor groove 248, both formed in the rotor face and adapted to transfer fluid. At the perimeter of rotor grooves 246 and 248, a fluid-tight seal is formed at the rotor-stator interface thus providing for the containment of any fluid within the rotor grooves and avoiding fluid leakage between the rotor and stator at the rotor-stator interface. Rotor 224 is rotatably movable about an axis of rotation 250, normal to and at the center of stator face 226, between two discrete angular positions with respect to stator element 222 (FIGS. 2A and 2B).
FIGS. 2A-2B show schematic views of the rotor-stator interface of the prior art valve of FIG. 1 in two discrete modes of operation, looking at the stator surface 226, with the rotor 224 being transparent. The valve 220 provides two position fluid output switching of two separate input fluids. The two modes of operation depicted correspond to the positioning of controlling rotor 224 in one of its two discrete angular positions indicated by markings xe2x80x9c1xe2x80x9d and xe2x80x9c2xe2x80x9d on rotor face 228. In the operation of the valve 220, the first fluid and the second fluid from the first and second fluid source, respectively, are pressurized by a suitable means, such as a pump (Not Shown), to provide a motivating force for fluid flow.
In a typical configuration, inlet ports 236 and 244 and outlet passages A, B, C, and D as well as rotor grooves 246 and 248 are all contained on an imaginary circle 252 concentric with axis 250 at the rotor-stator interface. All inlet and outlet passages are circumferentially spaced apart at an arc angle of about 60xc2x0 about imaginary circle 252.
As shown in FIG. 1 and FIG. 2A, in the first discrete angular position xe2x80x9c1xe2x80x9d of the valve, the first rotor groove 246 fluidly couples the first inlet passage 230 to the first outlet passage A, and the second rotor groove 248 fluidly couples the second inlet passage 238 to the third outlet passage C. Accordingly, as the first fluid flows through the first inlet passage 230 in the direction of arrow 234 of FIG. 1, the first rotor groove 246 directs the flow out of the first outlet passage A in the direction of arrow 235. Similarly, as the second fluid flows through the second inlet passage 238 in the direction of arrow 242, the second rotor groove 248 directs the flow out of the second outlet passage C in the direction of arrow 243.
In the second discrete angular position xe2x80x9c2xe2x80x9d of the valve, referring now to FIG. 2B, the rotor face is rotated 60xc2x0 counterclockwise (Position xe2x80x9c1xe2x80x9d of rotor grooves 246 and 248 is shown in dashed line). The first rotor groove 246, as shown, fluidly couples the first inlet passage 230 to the second outlet passage B, and similarly the second rotor groove 248 fluidly couples the second inlet passage 238 to the fourth outlet passage D.
Table 1 summarizes the operating modes of the prior art valve 220 when rotor face 228 is placed in each of its two discrete operating positions xe2x80x9c1xe2x80x9d and xe2x80x9c2xe2x80x9d.
Thus, it is possible with the prior art switching valve 220 to selectively direct the flow of the first fluid to the first outlet passage A while the flow of the second fluid is directed to the third outlet passage C (i.e., position xe2x80x9c1xe2x80x9d) or, alternatively, to direct the flow of the first fluid to second outlet passage B while the flow of the second fluid is directed to the fourth outlet passage D (i.e., position xe2x80x9c2xe2x80x9d). Simple reciprocation of rotor 224 between each of the two discrete operating positions xe2x80x9c1xe2x80x9d and xe2x80x9c2xe2x80x9d of valve 220 relocates the rotor grooves 246 and 248 to fluidly connect the two inlet passages 230 and 238 to different pairs of outlet passages A/C and B/D.
One problem associated with this arrangement, however, is that it lacks fluid flow routing versatility. For example, it is often desirable under certain circumstances relating to the operation of analytical devices and the like, to fluidly couple the first inlet passage 230 to the first outlet passage A while the second inlet passage 238 is fluidly coupled to the fourth outlet passage D. Similarly, it is often desirable to fluidly couple the first inlet passage 230 to the second outlet passage B while the second inlet passage 238 is fluidly coupled to the third outlet passage C.
In the current valve design, selective directing of the first and second fluids is accomplished in a xe2x80x9ctandemxe2x80x9d or xe2x80x9clinkedxe2x80x9d operation. That is, in a mutually exclusive manner, the second fluid is directed to third outlet passage C only when the first fluid is directed to first outlet passage A when the rotor is placed in first discrete position xe2x80x9c1xe2x80x9d, and the second fluid is directed to fourth outlet passage D only when the first fluid is directed to second outlet passage B when the rotor 224 is placed in second discrete position xe2x80x9c2xe2x80x9d. It is not possible with prior art valve 220 for the first fluid to randomly access one of either the first outlet passage A or the second outlet passage B and, at the same time, for the second fluid to randomly access, independently, one of either the third outlet passage C or the fourth outlet passage D. For example, with valve 220, it is not possible for the first fluid to access first outlet passage A while the second fluid accesses fourth outlet passage D.
It would be possible to connect an additional single three-way valve to one of the first or second outlet passages A or B or to one of the third or fourth outlet passages C or D and thereby to selectively redirect the flow of the first fluid or the second fluid, respectively, to achieve the random access functionality described. This valving arrangement would provide random access of the first fluid to outlet passages A or B and, independently, provide access of the second fluid to either outlet passages C or D, respectively, through selective manipulation of the series of valves, but this would increase cost and size, and reduce the reliability of the valving system.
Modern laboratories have limited bench space, and they demand extremely high system reliability, even while placing a high premium on economy. A integral dual valve that could automatically provide for the access of the second fluid to either outlet passage C or D independent of the flow of the first fluid to outlet passages A or B would reduce cost and size and would increase reliability. There is a need for a dual, three-way, switching valve that provides for random access of two fluids to two possible outlet passages for each fluid.
The present invention provides a random access, dual, three-way, fluid switching rotor valve that selectively directs the flow of a first fluid to either one of at least two alternate outlet passages and, simultaneously and independently, selectively directs the flow of a second fluid to either one of at least two different outlet passages. Accordingly, unlike the previous dual, three-way rotor valves, any combination of fluid flows between the outlets is attainable.
Briefly, the valve apparatus includes a stator body having a stator face lying in an interface plane and a rotor element having a rotor face oriented in the interface plane in opposed relationship to and contacting with the stator face in a fluid-tight manner. The rotor element is pivotable about a rotational axis for rotational movement of the rotor face to at least four discrete angular positions relative to the stator face.
The stator element defines two independent inlet passages each having one end fluidly coupled to a respective fluid source for supplying a fluid. Both inlet passages further include opposite inlet ports which terminate at the stator face. Additionally, the stator element further defines at least three stator slots, and at least four independent outlet passages each of which is in fluid communication with the stator face. The first two outlet passages correspond to the first inlet passage, while the last two outlet passages correspond to the second inlet passage. The rotor element includes a rotor face which defines at least two rotor grooves. This face is rotatably mounted to the stator face in a fluid-tight manner, and between a first, a second, a third and a fourth rotor position.
The inlet ports, the outlet passages, and the stator slots of the stator element, and rotor grooves of the rotor element and stator slots collectively form a channel set which is arranged such that, in the first discrete rotor position, the first inlet port is fluidly coupled with the first outlet passage through a rotor groove and the second inlet port is coupled in fluid communication with the third outlet passage through another rotor groove. In the second discrete position, the first inlet port is maintained in fluid communication with the first outlet passage, while the second inlet port is fluidly coupled to the fourth outlet passage. In the third rotor position, the first inlet port is then fluidly coupled to second outlet passage through a rotor groove and the second inlet port is coupled in fluid communication with the third outlet passage through another rotor groove. Finally, in the fourth discrete rotor position, the first inlet port is maintained in fluid communication with the second outlet passage, while the second inlet port is fluidly coupled to fourth outlet passage.
In one embodiment of the present invention, the first inlet port of the stator is disposed at the rotational axis of the rotor element which is also the central longitudinal axis normal to the stator face. The second inlet port, by comparison, is disposed on a first imaginary circle lying in the interface plane and co-axial to the rotor valve rotational axis.
The stator face further defines a first outlet port of the first outlet passage, and a second outlet port of the second outlet passage, both of which lie in the first imaginary circle. A third outlet port of the third outlet passage, and a fourth outlet port of the fourth outlet passages both lie on a second imaginary circle of the interface plane which is concentric to the first imaginary circle. The second imaginary circle is of a diameter larger than that of first imaginary circle.
A first stator slot formed in the stator face lies in the first imaginary circle and is in fluid communication with the first outlet port, while a second stator slot is formed in the stator face, in the first imaginary circle, and is in fluid communication with the second outlet port. The stator face further includes a third stator slot lying on the first imaginary circle which is in fluid communication with the second inlet port.
In this one embodiment, the rotor face includes a first rotor groove which provides fluid communication between the first inlet passage and the first and second outlet passages, while a second and third rotor groove provide fluid communication between the second inlet passage and the third and fourth outlet passages, depending upon which discrete rotor position (i.e., first through fourth) the rotor valve is disposed.
The first rotor groove extends substantially radially from the rotational axis of the rotor valve to the first imaginary circle, having an inlet end in continuous fluid communication with the first inlet port. An outlet end of the first rotor groove is contained in the first imaginary circle, and in fluid communication with the first stator slot when the rotor is placed in the first or second discrete position. Thereby, the first inlet port is maintained fluidly coupled to the first outlet passage when the rotor is placed in the first or second discrete position. By comparison, in the third or fourth discrete rotor position, the outlet end of the first rotor groove is maintained in fluid communication with the second stator slot. Thus, the first inlet port is maintained fluidly coupled to the second outlet passage when the rotor is placed in the third or fourth discrete position.
In the second portion of the valve, both the second and third rotor grooves extend in a direction substantially radially from the rotational axis of the rotor element. In both rotor grooves, a respective inlet end thereof lies on the first imaginary circle and a respective outlet end thereof lies on the second imaginary circle. The second and third rotor grooves are preferably identical in configuration, but are spaced-apart angularly about the rotational axis. Thus, in the first and second discrete rotor positions, the inlet end of the second rotor slot is maintained in fluid communication with the second inlet passage, via the third stator slot. However, in the first discrete rotor position, the outlet end of the second rotor groove is in communication with the third outlet port while, in the second discrete rotor position, the outlet end of the second rotor groove is in communication with the fourth outlet port.
In contrast, in the third and fourth discrete rotor positions, the inlet end of the third rotor slot is maintained in fluid communication with the second inlet passage, via the third stator slot. However, in the third discrete rotor position, the outlet end of the third rotor groove is in communication with the third outlet port while, in the fourth discrete rotor position, the outlet end of the third rotor groove is in communication with the fourth outlet port.